How to Read a Cannabis Lab Report (COA)
Every batch of cannabis sold legally in Nevada is tested by an independent laboratory before it can reach a shelf or a delivery vehicle. The document that comes out of that testing is a certificate of analysis — a COA. It is the most detailed factual record that exists about what you are buying, and almost nobody reads past the first number.
Here is how the whole document works.
First: confirm the report matches your product
A COA is only meaningful if it describes the batch in your hand. Match it on the identifier, not the product name.
- Flower, shake, and pre-rolls — the batch number and lot number on your package must match the report.
- Vapes, concentrates, rosin, and edibles — the production run number must match.
Product names repeat across harvests. Identifiers do not. Nevada also requires the COA to include a photograph of the product as the lab received it, which is a useful sanity check on its own.
The cannabinoid panel
Nevada requires labs to quantify five cannabinoids at minimum: THC, THCA, CBD, CBDA, and CBN. Many labs voluntarily report more.
The pairs matter. THCA is the acidic form found in raw cannabis; it converts to THC when heated. That is why Nevada’s potential total THC figure is a calculation rather than a direct measurement:
potential total THC = (THCA × 0.877) + delta-9 THC + delta-8 THC
The 0.877 is a mass ratio. THCA loses a carbon dioxide group during decarboxylation, and the resulting molecule weighs about 87.7 percent of what it started at. Note that Nevada’s formula includes delta-8 THC as a third term, which the generic version of this formula used nationally does not.
Two honest caveats. The word potential is doing real work — it describes a theoretical maximum conversion, and combustion or vaporization in the real world converts less. And Nevada flower results are reported as received, moisture included; labs here are prohibited from reporting on a dry-weight basis.
The terpene panel
When terpene analysis is performed, Nevada requires ten compounds to be quantified: alpha-bisabolol, alpha-humulene, alpha-pinene, terpinolene, beta-caryophyllene, beta-myrcene, beta-pinene, caryophyllene oxide, limonene, and linalool.
Terpene results are always reported values — there is no pass or fail. They are the aromatic compounds that give a given flower its particular smell and flavor, and reading them tells you far more about the character of a batch than the THC line does. Our terpene explainer covers what each one smells like.
One thing that confuses people: since 2022, Nevada requires terpene testing on flower and wet cannabis destined for extraction, but not on concentrates, edibles, liquids, or topicals. A blank terpene section on a vape COA usually means the panel was not required, not that the lab skipped it.
The safety panels — this is the pass/fail half
Everything above is a measurement. Everything below is a screening, and a failure means the batch cannot be sold.
| Panel | Applies to | Standard |
|---|---|---|
| Moisture content | Flower | Under 15% |
| Foreign matter | Most categories | None detected |
| Mycotoxins | Flower, extracts | Under 20 µg/kg total aflatoxins; under 20 µg/kg ochratoxin A |
| Heavy metals | Flower, extracts | Arsenic under 2 ppm; cadmium under 0.82 ppm; lead under 1.2 ppm; mercury under 0.4 ppm |
| Residual solvents | Solvent-based extracts | Under 500 ppm |
| Total yeast and mold | Flower / extracts | Under 10,000 / 1,000 CFU per gram |
| Enterobacteriaceae | Varies | Under 1,000 CFU per gram (flower) |
| Salmonella, pathogenic E. coli, four Aspergillus species | Most categories | None detected per gram |
| Water activity or pH | Edibles, liquids | Under 0.86, or pH under 4.6 |
| Pesticides, herbicides, growth regulators | Most categories | Nevada Department of Agriculture limits |
The pesticide rule is stricter than most people realize. Nevada operators may only use pesticides on a state-approved list. A listed pesticide above its limit fails — and any verified detection of an unlisted pesticide fails, at any amount.
Two structural rules worth knowing. A lot stays quarantined until its COA issues, and a failure generally means the entire lot or production run is destroyed. And only one laboratory may test a given lot without regulatory approval, which forecloses the practice of shopping a sample around until a better number comes back.
Reading the fine print
ND means not detected, which means below the method’s limit of detection — not a guarantee of absolute zero. The LOD and LOQ columns tell you how sensitive the method was. A report marked Amended in red at the top has been revised, and the reason must be stated on it. And a Nevada lab must be ISO/IEC 17025 accredited and financially independent of every other cannabis licensee, which is the structural reason its results mean anything.
The short version
If you only do three things: match the identifier, read the terpene panel alongside the THC number rather than instead of it, and confirm the safety panels passed.
From there, browse the strain library to see how lineage and aroma are described, read our flower buying guide, or see how delivery works.
Frequently asked questions
Does every product have a COA? Every batch sold legally in Nevada has been tested and has one. Whether a given retailer publishes it publicly varies.
Why is the number on my package different from the COA? The label figure is typically potential total THC, a calculated value. The COA shows the THCA and delta-9 THC measurements underneath it.
Are terpene percentages supposed to be low? Total terpene content in flower is commonly a small fraction of total weight. The relative proportions between compounds are more informative than the absolute figures.
Does a failed test ever reach customers? No. A lot is held until results issue, and failures are destroyed or, in a narrow set of cases and only with regulatory approval, remediated and retested against every standard.